Zeolite Membranes: From the Laboratory Scale to Technical Applications

Caro, Jürgen; Noack, Manfred; Kölsch, Peter

doi:10.1007/s10450-005-5394-9

Cited by 172 publications

(99 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…43 Starting from a randomly oriented seed layer on a planar surface, at first all seed crystals will start to grow at the same time and with the same face-dependent growth rates. After a certain time, which critically depends on the seed concentration on top of the surface, the crystals will meet their lateral neighbors.…”

Section: Chemistry Of Materialsmentioning

confidence: 99%

Oriented Zeolitic Imidazolate Framework-8 Membrane with Sharp H₂/C₃H₈ Molecular Sieve Separation

et al. 2011

View full text Add to dashboard Cite

In the past 10 years, porous metalÀorganic frameworks (MOFs) have established themselves in materials science. 1À3 The 3-D framework structures are formed by metal clusters or cations connected by organic linker molecules. On the basis of the organicÀinorganic hybrid character, MOFs have promise in a wide range of applications, e.g., gas storage, 4,5 medical applications, 6À8 catalysis, 9 sensor technology, 10,11 and molecular separation. 12À14 Basically, there are three options to use MOFs for molecular separation of liquid or gas mixtures: (i) by retaining one or more species from the liquid or gas phase by preferential adsorption in the pores, (ii) by different diffusivities of the species in the MOF, which is in the extreme case sterical size exclusion (molecular sieving) of one or more species, and (iii) the combination of (i) and (ii). One of the primary features that makes MOFs highly interesting for molecular separation is the so-called isoreticular design. 15 Linker molecules can be modified with functional groups or even completely substituted, maintaining the basic framework structure while altering adsorption and diffusion properties. 16 Membranes in general represent a cost and energy effective solution for industrial gas and liquid separation modified support. The mixture separation performance of membranes is characterized by the separation factor R i , j , which is defined after IUPAC as the ratio of the molar fraction of species i and j in the permeate, divided by the ratio of the molar fraction of species i and j in the retentate. 17 Currently, there are increasing numbers of successful attempts to prepare molecular sieving MOF membranes as thin, polycrystalline layers on top of macroporous support materials, showing separation factors up to 25. 18À27 For the preparation of MOF membranes, usually two basic techniques known from zeolite membrane fabrication are applied: (i) secondary growth crystallization, where in a first a step a seed layer is attached to the support and, subsequently, in a second step, grown to a continuous polycrystalline layer under solvothermal conditions, and (ii) in situ crystallization, where the polycrystalline layer is grown on the bare or chemically modified support in a one-step one-pot solvothermal synthesis. In situ crystallizations seem to be simple and, thus, the favored preparation route. However, they have the disadvantage of critically depending on high rates of heterogeneous nucleation on the support surface to successfully obtain continuous, well-intergrown MOF layers. Whether or not a high surface nucleation rate occurs depends on various factors, e.g., the surface chemistry of the support material (zeta potential, surface acidity, etc.). In secondary growth crystallizations, nucleation and crystal growth are decoupled, and hence, high nucleation rates and chemical interactions with the support material are less crucial.Recently, we reported on the preparation of ceramic-supported zeolitic imidazolate framework (ZIF) membranes. ZIF-type MOFs frequen...

show abstract

Section: Chemistry Of Materialsmentioning

confidence: 99%

Oriented Zeolitic Imidazolate Framework-8 Membrane with Sharp H₂/C₃H₈ Molecular Sieve Separation

et al. 2011

View full text Add to dashboard Cite

show abstract

“…Recent progress in synthesising nanostructured porous materials [10,12,13] has provided essentially unlimited options for the generation of purpose-tailored pore architectures. Therefore, there is an increasing demand for clarification of the main features of molecular transport in such systems [14,15]. The performance of chemical conversion by heterogeneous catalysis and of chemical separation by molecular sieving and selective adsorption with nanoporous materials may be notably enhanced by the application of materials with a bimodal pore structure.…”

Section: Introductionmentioning

confidence: 99%

Normal and anomalous diffusion of non-interacting particles in linear nanopores

Zschiegner

Russ

Valiullin

et al. 2008

Eur. Phys. J. Spec. Top.

View full text Add to dashboard Cite

Abstract. The diffusion of gas molecules in pores is determined by the collisions between the molecules as well as by the collisions of the molecules with the pore walls. In many applications the so-called Knudsen regime is of particular interest. In this regime the collisions of the molecules with the pore walls play the crucial role, while the inter-molecular collisions can be neglected. Here we study the influence of surface roughness on the coefficients of self (or tracer) diffusion and transport diffusion. Considering the first four iterations of a generalised fractal Koch surface, we construct pore models of different roughness. For these model pores we have performed detailed simulations of both diffusion coefficients using a cube-based algorithm. The molecular trajectories can be mapped onto Lévy walks to determine the diffusion properties. In linear two-dimensional (2d) channels we observe anomalous diffusion, which can also be induced in smooth and rough three-dimensional (3d) pores by anomalous reflection laws. Normal diffusion is found in convoluted 2d pores and in all 3d pores when a diffuse reflection law is applied.

show abstract

“…To run separation processes continuously and without recurring regeneration steps zeolite membranes have been developed and studied over the last decades [10][11][12][13][14][15][16][17][18][19][20]. With this development, the utilization of zeolite membranes was progressively investigated for catalytic reactions [21][22][23][24][25][26][27][28][29][30][31][32].…”

Section: Open Accessmentioning

confidence: 99%

Zeolite Membranes in Catalysis—From Separate Units to Particle Coatings

Dragomirova

Wohlrab

2015

Catalysts

View full text Add to dashboard Cite

Literature on zeolite membranes in catalytic reactions is reviewed and categorized according to membrane location. From this perspective, the classification is as follows: (i) membranes spatially decoupled from the reaction zone; (ii) packed bed membrane reactors; (iii) catalytic membrane reactors and (iv) zeolite capsuled catalyst particles. Each of the resulting four chapters is subdivided by the kind of reactions performed. Over the whole sum of references, the advantage of zeolite membranes in catalytic reactions in terms of conversion, selectivity or yield is evident. Furthermore, zeolite membrane preparation, separation principles as well as basic considerations on membrane reactors are discussed.

show abstract

Zeolite Membranes: From the Laboratory Scale to Technical Applications

Cited by 172 publications

References 45 publications

Oriented Zeolitic Imidazolate Framework-8 Membrane with Sharp H₂/C₃H₈ Molecular Sieve Separation

Oriented Zeolitic Imidazolate Framework-8 Membrane with Sharp H₂/C₃H₈ Molecular Sieve Separation

Normal and anomalous diffusion of non-interacting particles in linear nanopores

Zeolite Membranes in Catalysis—From Separate Units to Particle Coatings

Contact Info

Product

Resources

About

Zeolite Membranes: From the Laboratory Scale to Technical Applications

Cited by 172 publications

References 45 publications

Oriented Zeolitic Imidazolate Framework-8 Membrane with Sharp H2/C3H8 Molecular Sieve Separation

Oriented Zeolitic Imidazolate Framework-8 Membrane with Sharp H2/C3H8 Molecular Sieve Separation

Normal and anomalous diffusion of non-interacting particles in linear nanopores

Zeolite Membranes in Catalysis—From Separate Units to Particle Coatings

Contact Info

Product

Resources

About

Oriented Zeolitic Imidazolate Framework-8 Membrane with Sharp H₂/C₃H₈ Molecular Sieve Separation

Oriented Zeolitic Imidazolate Framework-8 Membrane with Sharp H₂/C₃H₈ Molecular Sieve Separation